American spelling vs Mycenaean civilization

American spelling and Mycenaean civilization both are nouns.

Word	Noun	Adjective	Verb	Adverb
American spelling	Yes	No	No	No
Mycenaean civilization	Yes	No	No	No

American spelling (noun)	Mycenaean civilization (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')	the late bronze-age culture of Mycenae that flourished 1400-1100 BC